Hi
To be honest, I don't remeber a company where I would be able to sit on my computer and create by myself my own user account into the company's domain - and it would be quite weird to allow a program to automatically create, delete and manage accounts into a domain (I dont' know if our network admin would let me run an application which creates any 20 skype random users accounts on our domain

) Using only local, not domain, user accounts, has a quite precise purpose, say "do what you want on your computer, crash it, viruse it, slow down it, but don't affect others".
We'll see, in my opinion this is a problem much beyond implementation, due to its security implications, overall all of us needs SIP-Skype communication, not security troubles.
vali